Circuit breaker



Oct. 19, 1948. T. LlNDsTRoM ETAL CIRCUIT BREAKER Filed Oct. l2, 1945 d.sa. 5, mma; m. EGB R vw. o ma# n A 9 win# .le ,m 9 MW 5T a i M7 ,Il .ne

CIRCUIT BREAKER Ture Lindstrom, Edgewood, Pa., and Albert H.

Baylis, Ypsilanti, Mich., assignors to Westinghouse.ElectricCorporation, East Pittsburgh, Pa., a corporation of PennsylvaniaApplication October 12, 1945, Serial No. 622,048

(Cl. 20o-108) 26- Claims. 1

This invention relates to circuit breakers and more particularly, tocircuit breakers of the type that are tripped instantaneously onoverload currents above a predetermined value and after a time delay onlesser overloads.

An object of the invention is to provide a circuit breaker having animproved trip device which is of simple construction, reliable inoperation and inexpensive to manufacture. f

Another object of the invention is to provide a circuit breaker with animproved electromagnetic trip device having a magnetic piston sealed ina casing containing a body of uid which is moved relative to the pistonby an armature disposed externally of said casing while the magneticpiston is restrained against movement by the magnetic forces to providetime delay tripping of the breaker. v

Another object of the invention is to provide a rcuit breaker with animproved electroresponsive trip device comprising a sealed casingcontaining a body of fluid, the casing being moved by an armature totrip the breaker and having a magnetic piston disposed within the casingto delay movement of the casing. Y

Another object of the invention is to' provide a circuit breaker with animproved electromagnetic trip device wherein the tripping armature isnormally latched and is released to trip the breaker after a time delayby the movement of a sealed casing relative to a magnetic piston whichis disposed within the casing and held substantially stationary by themagnetic forces during tripping movement of the casing.

Another object of the invention is to provide a circuit breakeraccording to the preceding paragraphs wherein sealed casings havingdifferent.'

lar inthe appended claims. The invention itself,

however, both as to structure and operation, together with additionalobjects and advantages thereof, will be best understood from the follow-2 ing detailed description of one embodiment thereof when read inconjunction with the accompanying drawing, in which:

Figure 1 is a side elevational view, partly in section, ci a. circuitbreaker embodying the invention,

Fig. 2 yis a front elevational view of the trip device with the coverplate removed,

Fig. 3 is a front elevational view of the trip device showing the coverplate, and

Fig. 4 is an enlarged sectional view oi.' the movable core structure.

Referring to Figure 1 of the drawings, the reference numeral ildesignates a base of strong insulating material which supports thevarious parts of the circuit breaker. A pair of terminals I3 and I5 aresuitably secured to the base andy each terminal hasone or moreconnecting studs i9 which extend through the back ofthe base and serveto electrically connect the'breaker to the circuit which it controls.

The upper terminal I3 has a contact block 2| of rigid conductingmaterial secured thereto; and a rigid contact block 23 secured to thebase is electrically connected to the lower terminal i5 through theenergizing winding of the trip device of the breaker, which will behereinafter described.

'Ihe contact means and mechanism of the circuit breaker illustrated aresimilar to the circuit breaker fully disclosed in Patent No. 2,214,471,is-

sued September 10, 1940 to Leon R. Ludwig and Merle E. Horn, andassigned to the assignee of the present invention. Hence only a briefdescription of these parts will be given in this application.

The main stationary contacts 25 and 21 are rigidly secured to thecontact blocks 2| and 23, respectively; and the auxiliary stationarycontacts29 and 3| are secured to a triangularlyshaped contact platform33 of conducting material which is mounted on the upper portion of theblock 2| for limited tilting and rocking movement by means of pins 35projecting from the opposite sides of the platform which engage in slots31 provided in a pair of side Walls 39 secured to the block 2|. Theplatform 33 is biased outwardly from the base by a plurality of springs4| and 43, and outward movement of the platform is limited by theengagement of the pins 35 with the outer ends of the slots 31 and bystop projections 45 carried by the platform adjacent its upper end. Theplatform 33, and consequently, the auxiliary contacts 29 and 3| areelectrically connected to the terminal I3 by means of a flexible shuntconductor 41.

ries a main contact,bridging member 55 lfor bridging the main contacts25 and 21, and an auxiliary contact member 51 for engaging thestationary auxiliary contacts29 and 3|, the auxillary contact membes 51beings'ecured to the upper end ci the channel-shaped contact arm 49 bya.

plurality of screws 59. Y I

' The main contact bridging member 55 is formed of rigid conductingmaterial, and is loosely A mounted on, the contact arm 49 for limitedmovement relative to the contact arm toward and away from the maincontacts 25 and21,by A

means of a pair of studs' 8| secured to the contact carrying arm 49,only one stud being shown? A pair oi.' coil springs (not shown) encirclethe studs 6|, and are disposed between the contact carrying arm 49 andthe bridging member 55 for biasing the bridging member toward, the

stationary main contacts 25 and 21 with a predetermined force. The -endsof the bridging member 55 are beveled to-lie parallel with the bevelededges of the contact blocks 2 Land 23, and have a'pair of contacts 81secured thereto for engaging the main stationary contacts 25 and 21.

The auxiliary contact member 51 is fofmed of f rigid conductingmaterial, and has an intermediate contact $9 and an arcing contact` 1|secured thereto for engaging the intermediate and arcing contacts 29 and3| of the stationary contact means.

A exible shunt conductor 1.3 electrically con-l nects the auxiliarycontact arm 49 to the main stationary contact block 23. The exibleconductor 13 has its upper end secured to the contact arm 49 by thelower screws 53. The lower end of the exible shunt conductor 13 issecured to the lower contact block 23 by means of 'a bolt y11.4

IThe switch member 5 I 'has a yoke-shaped lower end which is pivotallymounted between the sidewalls of a main frame 19 by means of the pivotpin 8|. The switch member 5| is movable about its pivot axis to open andclosed circuit positions to open and close the contact means of thebreaker by means of 'an operating mechanism indicated generally at 88. fy

The operating mechanism 83 is supported by tl'ie-main frame '19 andcomprises an actuating lever'95 pivoted on a pin 81' carried by theframe,

, and isconnected to the switch member| 5| by a link 99. An operatingmember 9| is also pivoteci on the pin 81 for movement about the sameaxis as'the actuating lever 85. The actuating lever -85 is normally andreleasably connected to the operati member 9| for movement thereby byAmeans .of a pair of latches 93 and 95, which are v vpivotally mountedon the lever 85 at 91 and 99,

The latch 93 engagesa roller |0| respectively. A carried by theoperating member 9|, and this latch is, inL turn, held in latchingposition by the auxiliary latch 95. Theoperating member 9| is adapted`to be releasably held in closed 'cir--l cuit position by means of a mainholding latch |03 pivoted at ||9, which releasably. engages the roller-|I. with a curved tailpiece by means or which it is `released to causerelease oi' the latcl 93 and consequent tripping of the circuit, breakerby the release oi the actuating lever 85 from its connection with theoperating member 9|. When The auxiliary latch 95 is providedA l releasedthe actuating member 95 moves in a counterclockwise direction about thepivot axis 81, causing` opening of the movable contact means.

member 9|. 'I'he switchv member 5| and the Iactuating lever 35 arebiased to open position by means of a pair of accelerating springs |99(only one being shown), which are connected at their upper ends to theswitch member 5| and at their lower ends to the sides of the'main frame1-9.

To close the circuit breaker after it has been tripped open, theoperating member 9| is iirst moved in a counterclockwisedirection aboutthe pivot axis 81 to the open position to eiect resetting of the latches`and reestabishment ofV the releasable rigid connection between theactuating lever 35 and the operatingmember 9|. After the rigidconnection is thus established, the operating member 9| is moved in aclockwise direction to-closed position by means of a handle III to eiectclosing of the contact means of the breaker. The clockwise or closingmovement 4of the operating member 9i is limited by a portion 92 thereofstriking a iixed stop 94 on the frame 19. When the parts have been movedto closed position, the main holding latch |93 reengages the roller ||l|to hold the operating member in closed position.v The stop 94 is locatedto permit a slight overtravel of the member 9 Iv to insure properengagement, of the latch |93 with the roller IUI. It will be noted thatthe construction oi -the operating mechanism is such that the movablecontactlmeans is trip-free of the operating member 9|; that is, when thebreaker Iis tripped, the contact means move to open positionirrespective'of the position oi the operating member 9|.

The mounting arrangement of the contact means is such that duringopening of the breaker the main'lbridging`member`55 is iirst separated yfrom the stationary contacts 25 and 21, while the auxiliary contactsremain in engagement by reason of thehoutward movement of the contactplatform -33 under the inuencefof the biasing springs 4| and`43. .Afterthe bridging member has separated a predetermined distance from the mainstationary contacts, the intermediate contacts 2 9 and 99 begin toseparate. This takes place as soon as the pins 35 engage the ends of theslots 31. During this time, thearclng conf, tacts 3| and 1i remain inengagement -due to the rocking movement of the contact platform 38.After the intermediate contacts have separated a predetermined distance,the arcing contacts 3i and 1| begin to separate. During closing. thelcontacts engage in the reverse order, as will readily be understood. Itwill thus be-seen that the arc formed during separation of the contactsis drawn onlybetween the arcing contacts 3| j and 1|.- The circuitbreaker is adapted to be tripped open either manually, or automatically,in re- `sponse to predetermined overload conditions in the circuit, bymeans of a trip device indicated Y i5 ldetermined 'overload conditionsto move the trip acentos l lever |11 to tripping position to causeautomatic openin of the circuit breaker.

One m |23 of the trip lever ||1 is odset and extends inwardly toward thebase of the circuit breaker, and has its inner end disposed immediatelyabove the trip means |2 to be engaged and moved by a plunger of theelectromagnet to effect automatic tripping of the breaker. The

arm |23 of the trip lever is provided with a pro` position and the triplever to its normal inoperal tive position, as shown in Fig. 1.

The electromagnet 12| comprises spaced stationary core members |3l, atripping armature |33 having a trip rod |35 seated in an openingthereon, an energizing winding |31 having one end connected to thecontact block 23 and the other end connected to the terminal |5. Thetrip rod |35 extends through an opening in a movable armature |39 but isnot operated directly thereby. Disposed within the energizing winding|31 is a movable core structure indicated generally at |4| (Figs. 1 and4).

The movable core structure comprisesa sealed casing |43 of anon-magnetic material containing a body oi' oil or other liquid o!suitable viscosity. The casing |43fis disposed for vertical movement inthe 'winding |31 and has its upper` end operatively connected to themovable armature |39 by' means of a lever |45. The lever |45 comprises apair of spaced parallel levers connected by a yokek |41 and pivoted on,a pin |49 supported in the spaced, upwardly extending 7 arms of abracket |5|4 which is secured to the upper ilxed core member |3i.pivotally connected to the upper end of the casing |43 by means of a pin|53 which extends Ythrough openings in projections on the upper end ofthe casing. The opposite endci the lever |45 is connected to the movablearmature |39 by means of pins |55 which extend through openings in thearms of the lever |45 and through corresponding 1openings in projections|51 lextending upwardly. from each side of Ithe movable armature |39.Thus, when the movable armature |39 moves downward, the sealed casingi43,

due to the lever |45, will move upward.

underside of the lower iixed core |3|. The other arm |11 of the bellcrank lever |59 extendsinto the path o! travel o! a projection |19extending from the bottom member |5| of the sealed casing |43. The bellcrank lever is biased in a counterclockwlse direction to latcbingposition by means of a double spring |53 coiled around the pin |1| oneither side oi the bell crank |99. The bight of the spring |53 engagesthe latch arm of the bell brank |59 and the two ends of the spring bearagainst a yoke |55 integral with Athe side members |13 oi the bracket|15. The latch arm |91vengages a latch member |91 secured to the 4 irontof the tripping armature. |33 to releasably restrain the trippingarmature against operation.

A spring |39 tensioned between the pin |53 ci the lever |45 and abracket i9| suitably secured to the upper fixed core member |31 normallybiases the movable core, structure i4! and the movable armature 139toward a central position. With normal current flowing in the energizingcoil the weight of the movable core structure is sufcient to cause 'theparts to assume the positions in which they appear in Figure 1.

When an overload current below ay predetermined value of, for instance,1000% of normal rated current occurs the magnetic forces attract themovable armature |39 and the tripping armature l'33'iioward each other.Since the tripping armature |33 is latched in its retracted position itcannot move, but the movable, armature |39 starts to move downward and,through the agency of the pivoted lever |45 draws the sealed casing |43upwardly and eventually the projection |19 on the bottom member 19| ofthe casing |43 engages the arm |11 of the bell crank |69 and operatesthe bell I crank and the latch arm |31 to release the tripping armature|33. The' tripping armature |33 immediately moves upwardly carrying thetrip' rod |35 therewith to engage the trip lever ||1 and trip thebreaker in the manner previously described.

lWhen an overload below the afore-rnentioned predetermined magnitudeoccurs, such, for instance, as is occasioned by the turning on oflights, it is desirable to interpose a time delay between the occurrenceof the overload and the tripping of the breaker, so that, should thecircuit condition return to normal before tripping is effected, the tripdevice may return to normal condition without having tripped thebreaker.

The movable armature |35 Vand the tripping armature |33 are guided intheir 'vertical reciprocal movement by means of a guide bracket |59 ofnonmagnetic/material having formed over portions '|51 (IllgfZl/securedby means of rivets |53 to bottom and top sides` respectively of theupper and lower fixed core members |31. Channel-shaped guides |55 areformed outwardly :from the bracket |55 one embracing each side of thearmature |39 and the tripping armature |33, to guide said armatures intheir vertical movements.

Y The tripping armature |33 is normally latched in i-ts unattractedposition by means of a latch member |51 which forms one arm of a bellcrank lever |55 pivoted on a pin |1| supported between the downwardlyextending portions |13 ci a bracket |15 (see Figs. 2 and 3) secured tothe In the present invention time delay is effected by a piston |93 ofmagnetic material disposed in the sealed, casing |43 and normally biasedby means of a compression spring |95 to the upper end of the casing. Thespring |95 is compressed between a flange |91 of magnetic materialintegral with a core member |99 also of magnetic material in the bottomof the casing and thc bottom of the piston |93 inside a cylindricalextension 20| of the piston. The piston |93 is spaced from the top ofthe casing |43 by means' of a stop 203 secured to and projectinginwardly from the top of the casing. The piston |93 is provided with twooil passages 205 and 281 extending longitudinally therethrough. Thepassage 201 is for the purpose oi relieving the oil pressure from abovethe piston to permit its restoration following an operation and to -thisend is provided with a ball check valve 2119r vclisposed in the enlargedlower end 2|| of the passage and loosely retained therein by means of apin 213. When the casing |43 is moved upwardly past the piston |93during the occurrence of an overloadvl the oil pressure presses "theball` 2119 7 against a conical seat thus closing the passage 201.

A ball valve 2|5 is disposed in the enlarged upper portion 2|8 of thepassage 205 and is biased downwardly' against a conical seat by a spring2|7 compressed between the head 2|9 of a guide rod 22| and a pin 223inserted in suitable openings inthe piston and extending diametricailyacross the enlarged portion 2| 8 of the passage 205. The guide rod 22|is provided with an axial slot at 225 embracing the pin 22,3. The pin223 may be assembled in any one of a plurality of openings 224 (threebeing shown) provided therefor in the piston to vary the compression ofthe spring 2|`| thereby varying the pressure at which the valve 2|5 willopen. The purpose of this adjustment will be more fully described later.

The trip device operates with time delays of dlilerent duration in twodistinct ranges of over load currents below a predetermined magnitude.and instantaneously in response to an overload above the predeterminedmagnitude, or a short circuit. These ranges of overload currents may bearbitrarily defined as, for instance, low range up to 200% of normalcurrent, intermediate range between 200%V and 1000% of normal, andinstantaneous 1000% or more of normal current. Assuming an overloadwithin the low range of overload currents, the operation of the tripdevice will now be described.

Upon the occurrence of an overload in the low range, the winding |37becomes energized and the magnetic forces across the air gap between thearmature |39 and the tripping armature |33 attracts these armaturestoward each other, but, since the tripping armature is latched andcannot immediately move, the armature |39 is drawn downwardly. Thedownward movement of the armature |39 acting through the lever |95 (Fig.l) and aided by the spring |89 starts to move the sealed casing |43upwardly. The piston |93 is so disposed in the magnetic field that themagnetic forces hold it substantially stationary while the casing |23 isdrawn upwardly past it by the armature |39. As the casing |23 starts tomove upwardly,lthe pressure of the oil below the piston closes the checkvalve 209 (Fig. 4) compelling the oil to fiow through the passage ,205or between the piston and the wall of the casing. The spring 2|7 holdsthe valve 2 l5 closed on overloads up tov 200% of normal or in the lowrange of overloads, consequently, the oil ows, around the piston in thisrange of overloads, thus providing a relatively long time delay.

Continued movement of the armature `|28 reduces the air gap between thearmatures |92 and |33 and 'increases the forces acting thereon. This iscounteracted to a certain extent after the spring |89 (Fig. 1) passesabove center where it opposes upward movement of the sealed casing.Eventually, after at time interval which. varies inversely with themagnitude of the overload, the projection |79 (Fig. 1) on the bottom ofthe casing engages the arm |77 and operates the bell crank |69 torelease the tripping amature which then moves upwardly to trip thebreaker in the previously described manner. Additional magnetic pull isprovided to unlatch the armature |33 ,by the core member |99. As thecasing |63 moves upwardly the core |99 reduces the air gap betweenitself and the magnetic piston |93 thus increasing the upward pull onthe casing.

When the breaker is tripped open the circuit is interrupted and thewinding |31 of the trip device becomes deenergized. At this time, the

v tripping means. pression spring 229 compressed between a bracket 23|(Figs. 2 and 3) mounted on the right hand spring |89 exerts a force onthe lever |45 biasing the lever in a counterclockwise direction. Thisforce raises the armature |39 and lowers the movable core structure |4|until the spring |89 and the lever |45 are in line. Thereafter theweight of the core structure |.4| restores the casing |43 and thearmature |39 to the normal unattracted position. During the restoringmovement the entire movable core structure moves downwardly as a unit,and, at the same time, the spring |95 forces the piston |93 upwardlyagainst the stop 203 (Fig. 4). The-pressure of the oil above the piston,during the restoring action, opens the check valve 209 permitting freeflow of oil through the passage 207 to the other side of the piston'thus providing for quick resetting of the piston. When the trip deviceis deenergized upon opening of the breakenthe tripping armature |33drops immediately to its unattracted position where it is relatched bythe latch |67 under the inuence of the spring |83.

The operation of the trip device upon the occurrence of an overloadcurrent in the intermediate range, that is, between 200% and 1000% ofnormal current, is the same as the operation just described withlthevdiierence that the pressure oi the oil in the casing |43 below thepiston is greater due to the greater energization of the electromagnet.When the winding |37 is energized in response to an overload ofapproximately 200% of normal current or more, the pressure is suicientto compress the spring 2 7 and open the valve 2|5 thus providing for agreater flow of oil to the other side of the piston |93 which results ina shorter time delay in the intermediate range of overloads than in thelow range where the valve 2|5 does not open.

The breaker is tripped open instantaneously in response to overloadcurrents above the aforementioned predetermined value, or in response toshort circuits by means of a small instantaneous trip armaturecomprising an iron screw 227 screwed into the lower end of thenon-magnetic trip rod |35 and seated in the opening in the trip armature|33. Upon the occurrence of an overload current above the predeterminedvalue or a short circuit, the armature 227 is attracted upwardly tobridge the air gap between armatures |33 and |39 and actuates the triprod |35 to instantaneously trip the breaker independently of thetime-delay mechanism and independently of the armature |33 and |39. Whenthe circuit is interrupted and the trip device deenergized, the trip rodand the armature 227 return to their unattracted positions by theirown-weight. The trip armature |33 remains latched and is not operated oninstantaneous tripping operations.

The minimum overload current `required. to instantaneously trip thebreaker may be varied by varying the size or mass of the screw 227cornprising the instantaneous trip armature.

Means is lprovided to calibrate the time delay This means comprises acompin |55 which connects the lever |35 to the armature |39, and a block233 threadedly engaging a rotatable rod 235. The rod 235 is disposedvertically and the reducedl upper end thereof engages a suitable openingin the bracket 23|. The lower threaded portion of the rod 235 isrotatably supported on the lower fixed core member |3| by means of acollar 237 secured to the rod and resting on the core member |3|. Thelower end of the rod 235 belowthe core member IBI is provided with aknurled knob 239 which is secured thereto for rotating the rod.

Rotation of the rod 235 moves the block 233 up or down depending on thedirection of rotation and varies the compression of the spring 229 whichopposes operation of the armature 139 thus varying the overload currentrequired to effect tripping of the breaker. The block 233 is preventedfrom turning with the rod 235 bya projection 24i lthereon extendinglthrough an elongated slot 243 extending vertically in a scale plate 245.The scale plate 245 is suitably secured to the front of the trip deviceand bears a scale indicating the percent of overload current required totrip the breaker. Y y

There is also provided means -for changing the low and intermediateranges of overload currents required to trip the breaker; viously setVforth that With the pin I223 mounted in the upper one of the holes 224,the low and intermediate ranges o! overload currents were respectively100% to 200% of normal and 200% to 1000% of normal current. If the pin2,23 is assembled in the intermediate hole 224, the spring 2H will begiven a greater compression and will require a greater pressure andconsequently a higher current value to open the valve 2 I5. The lowrange of overloads with the pin 223 in the intermediate hole 224 maythen be 100% to 300% of normal current and the intermediate range may befrom .300% to 1000% of normal current value. 223 in the lower one of theholes 224 may-establish the low range of overload currents at from 100%to 400% of normal and the intermediate range from 400% to 1000% ofnormal current values. The limits of the low and intermediate ranges ofoverloads set forth ,are to be considered merely by way of example andthese may bevaried considerably. to suit particular requirements. Forinstance, by the provision ofa stronger or weaker spring 2I1 entirelydiierent sets of values may be established.

The movable core structure |4I including the casing i43 is readilyremovable from the trip device by removing the pin |53 and dropping thecasing assemblage out of the magnet. other casing assemblage havingdifferent operating characteristics may then be inserted. YFor instance,three dierent casing assemblages may be provided and interchangeablyinstalled in theV breaker, each. of the casing assemblages having thepin 223 inserted in a diierent hole'2-24 and/or having diilerentstrength springs 2I'I assembled therein. Each of the c asings may bemarked with identication corresponding to one of the three time-currentcurves marked von the scale plate 245 (Fig. 3). e

By latching the tripping armature agains movement and then releasing itafter the magnetic airgap is substantially reduced the maximum magneticpull is utilized to trip the breaker. When released, the trippingarmature |33 is actuated to trip the breaker unopposed by theCalibrating spring 229.

Having described the invention in accordance with the patent statutes,it is to be understood that various changes and mociications4 may bemade in the structural details and combination of elements disclosedwithout Adeparting from some of the essential features of the invention.It is therefore, desired that the language of the appended claims begiven as reasonably broad interpretation as the prior art permits.

It was pre- In the same manner assembling the pin- We claim as ourinvention:

movable contacts and operating mechanism therefor, the combination of atrip member operable to eiect automatic operation of saidoperatingmechanism, an electromagnetic trip device comprising anenergizing winding, a rst armature operable to effect operation of vsaidtrip member, means comprising a sealed casing movable to cause trippingoperation of said ilrst armature, a second armature for moving saidcasing, and means disposed in said casing and responsive to energizationof said electromagnet to delay tripping movement of said iirst armature.

2. Ina circuit breaker comprising relatively movable contacts andoperating mechanism therefor, the combination of a trip member operableto effect automatic operation of said operating mechanism,anelectromagnetic trip device comprising an energizing Winding, a firstarmature operable to effect operation of said trip member, meansvcomprising a sealed casing disposed in said winding and movableto'cause tripping operation of said first armature, a second armaturedisposed outside of said winding-for operating said casing, and meansdisposed in said casing and responsive to energization of saidelectromagnet to delay tripping operation of said iirst armature.

3. In a circuit breaker comprising relatively movable contact andoperating mechanism therefor, the combination of a trip member operableto effect automatic operation of said operating mechanism, anelectromagnetic trip device for operating said trip member comprising anener- Igizing winding, a tripping armature operable to cause operationof said trip member, a nonmagnetic casing movable to effect operation ofsaid tripping armature, a second armature movable relative to saidcasing by said electromagnetto move said casing, and a magnetic memberdisposed in said casing /and responsive to energization of-said windingto oppose movement of said tube.

In a circuit breaker comprising relatively movable contacts kandoperating `mechanism therefor, the combination of a trip member operableto eiiect an operation of said operating mechanism, a trip device foroperating said trip member comprising an energizing winding, a rstarmature movable to trip the breaker, means releasably restraining saidfirst armature against tripping` movement, a casing movable to operatesaid restraining means to release said first armature, a second armatureoperatively related to said casing and operable upon.energizat1on ofsaid windingto move said casing, and means disposed in said casingresponsive to energization of said windingv to retard movement of saidcasing.

5. In a circuit breaker comprising relatively movable contacts andoperating mechanism therefor, the combination o'f a trip member operableto effect automatic operation of said operating mechanism, anelectromagnetic trip device for operating said trip member comprising anenergizing winding, a, tripping armature, means releasably restrainingsaid tripping armature against movement, means comprising a sealedcasing movable to operate said restraining means to permit operation ofsaid tripping armature, a movable `armature for moving said sealedcasing, and means comprising a piston of magnetic material disposed insaid casing for' delaying movement oi said casing. I l 6. 'In a circuitbreaker comprising relatively movable contacts and operating mechanismthereto the combination of a trip member operable to eiiect operation oisaid operating mecha-g nism, an" electromagnetic trip deviceliorperating said trip member comprising a fiixed, magnetizablestructure, an energizing winding, a releasable member operated by, saidelectromagnet and operable when released to operate said trip member, acasing movable to efiect release of `said releasable member, an amatureoperable upon energization of saidj `winding to move said casing toeiiect release of said releasable member, V and a magnetizable member insaid casing responsive to energization of said winding toretard movementof' said casing.

'7. In acircuit breaker comprising relatively movable contacts andoperating mechanism therefor, the combination of a trip member operableto effect operation of said operating mechanism, an electromagnetic tripdevice for operating said trip member comprising a ilxedf magnetizablestructure. an energizing winding, a releasable member operated by saidelectromagnet and\operable. when released to operate said-,trip member,a casing movable to elect release voi said releasable member. anarmature operable upon energizationof said winding to move said casingto effect release oi' said releagsable member, Laimagnetizable member-in said casingV responsive to energization of said winding tretardmovement of said casing, and means operable by said electromagnetindependently oi said releasable member to operatel said trip member. Y

8. In a circuit breaker comprising relatively movable contacts andoperating mechanism therefor, the combination of an electromagnetic tripdevice for causing an automatic operation oi' Ysaid operating mechanismcomprising a magnetic circuit, an energizing winding, a releasablemagnetizable l member yin the magnetic ,circuit movable when released toeiiect tripping oi the breaker, a sealed element movable to release saidreleasable member, a second magnetizable member in said magnetic circuitoperable in response to' overload currents insaid winding to move saidsealed element to release said releasable member,

andtime delay means comprising a magnetizable member sealed in saidelement and disposed in said magnetic circuit to be restrained againstmovement in response to overload currents to oppose movement of saidelement.

9. In a circuitbreaker comprising relatively movable contacts andoperating means therefor, the combination of a trip member operable tocause automatic operation oi said operating means, an' electromagnetictrip device for operating saidtrip member comprising .a magneticcircuit, an energizing winding, areleasable' magnetizable member in saidmagnetic circuit operable 1in response to overload currents below apredetermined value in said winding to operate said trip member, asealed casing disposed in said winding and movable to release saidreleasableV member, a first amature in said magnetic circuit operableinresponse to overload currents below said predetermined value in saidwinding to move saidcasing, time delay means comprisingv amagnetizable'member sealed insaid casing and disposed in said magneticcircuit to be restrained against movement by energization'oi saidwindcasing. and a second amature in said magnetic circuit operableindependently of said Jreleasable member in response to overloadcurrents above said predetermined value to instantaneously 5 operatesaid trip member.

10. In a circuit breaker comprising relatively movable contacts andoperating mechanism therefor, 'the combination of a trip member operableto effect automatic operation of said operating mechanism, anelectromagnetic trip device comprising an energizing winding. a'rstarmac ture operable to eiect operation of Vsaid trip member, meanscomprising a sealed casing movable to cause tripping operation of saidnrst amature, a second amature for moving'said casing, means disposed insaid casing and responsive to energization oi said electromagnet todelay trippingV operation of said first amature, and adjustable meansfor varying the operating characteristic of said second armature. 1 -f1l. In a circuit breaker comprising relatively movable contacts andoperating mechanism therefor, the combination oia trip member operableto enect automatic operation of said oper- '25' atingv mechanism, anelectromagnetic trip device comprising an energizing winding, a rstarmature operableto efiect operation of 'said tripA member, meanscomprising a sealed casing mov- I ableto cause tripping operation oisaid iirst 36 armature, asecond armature for operating said casing.means 'disposed in said casing and-re- .sponsive' to energization oisaid electromagnet to delaytrippingoperation of said rst armature;

resilient-means opposing operation oi said second 33 armature, and meansoperable to vary the tension 'of said resilient means to vary theoperating characteristic of said trip device.

12. In a circuit breaker comprising relatively movable contacts andoperating mechanism 4h therefor, the combination of a trip memberoparable tdelect automatic operationof said operating mechanism, anelectromagnetic tripdevice comprising an energizing winding, a iirstarmature operable to edect operation ofsaid trip member, meanscomprising'a sealed casing movable -to cause tripping operation of saidfirstarmature, a second armature for operating said casing, spring meansbiasing said-casing against tripping movement during the iinal part ofthe tripping movement and tohus Vopposing tripping op,-4

eration of said casing. and means disposed in said casing and responsiveto energization of said electromagnet to delay tripping operation o'fsaid iirst ing mechanism, an elcctromagnetic'tripl device 6o' comprisingan energizing winding. a rst arma- A ture operable to effect operationof sad trip member,-rneans comprising a sealed casing movable to causetripping operation ofl said n rst armature, a

second amature for moving said casing, a spring associated with saidcasing to rst bias said casing in tripping direction and then toopposestrlpv ping movement of said casing, and means disped in saidcasingand responsive to energization of said electromagnet todelay'tripping operation of 7o saldrst amature. le. linV a circuitbreaker comprising relatively movable contact A and operating mechanismtherefor, the combination of a tri-p member oping in response tooverload currents below said erable to edect automatic operation of saidoppredetermined value to retard movement oi said erating mec anelectromagnetic trip deyture against movement, a non-magnetic casing 13`vice for operating said trip member comprising an energizing winding; atripping armature operable to cause operation of said trip member, latchmeans normally restraining said .tripping armamova'ble` to operate saidlatch means to release said tripping armature, a secondarmature movablerelative to said casing by .said electromagnet to move said casing, anda magnetic member dis- -posed in said casing and responsive toenergization ofsaid winding tooppose movement of said casing.

`l5. In a circuit breaker comprising relatively l movable contacts andoperating `mechanism therefor, the combination of a trip memberopermined value to move said chamber, time delay means comprising amagnetic member disposed in said chamber to be restrained againstmovement in response to overload currents below said predetermined valueto retard tripping operation ofv said chamber, means operable by saidrst armature to actuate said .trip member, and a third armature on saidmeans operable in response to overload currents above said predeterminedvalue to operate said means independently offsaid rst 4armature and said`second armature to instantaneously operate the trip member. f

16. In a circuit breaker comprising relatively movable contacts andoperating means therefor, the combination cfa trip member operable toeffect automatic` operation of said breaker, an electromagnetic tripdevice for operating said trip member comprising an energizing winding,a first farmature operable to effect operation of said trip member, anelement operable by said nrst armature to operate said .trip member,means comprising a sealed chamber movable to eiect tripping operation ofsaid first armature, a second armature operable by said trip device inresponse to overload 4currents below a predetermined value to move saidchamber, .time delay meanscomprising means disposed in said chamberresponsive to energiza'tion of said winding to retard tripping movementof said chamber, and magnetic meansfI on said element operable inresponse to overload currents above said predetermined value to operatesaid element independently of said iirst armature to instantaneouslyoperate said trip mem- 17. In a circuit breaker comprising relativelymovable contacts and operating mechanism therefor, the combination of atrip device operable to effect automatic operation of said breaker, saidtrip device comprising an energizing winding,` a Areleasable armatureoperable to trip said breaker, means comprising a sealed casingcontaining a body of uid, said casing being disposed within said Windingand movable upon energization thereof to effect release of saidreleasable armature, time delay means comprising a magnetizable coredisposed within said casing and restrained against movement with saidcasing by energization of said winding, said core having a passagetherein for permitting iluid to flow from one side of said core to theother, valve meansfor con- 75 .trolling the rate of ilow of said uld tothereby control the rate of movement of said casing, and means foradjusting said valve means to vary the rate of flow of said uid tothereby vary the operating characteristic of the trip device.

18. In a circuit breaker comprising relatively movable contacts andoperating mechanism therefor, the combination of a trip device operableto eiect automatic opening of said breaker, said trip device comprisingan energizing winding, a releasable armature operable to .trip thebreaker, means comprising a sealed casing containing a `body of iluid,lsaid casing being movable to effect release o! said releasable armature,a second armature ior moving said casing, time delay means comprising amagnetizable core disposed in said casing and restrained againstmovement Iby energization of said winding, said core having a passagetherein to permit uid to pass from one end of said `casing to the other,valve means for controlling t'he rate oi ilow of said fluid to therebycontrol -the rate of movement oi' said casing, and means for adjusting.sa-id valve means to van the rate of ilow yof said fiuidto thereby varythe operating characteristics of said trip device.

19. In a circuit breaker comprising relatively l movable contacts andoperating means therefor,

the combination of a trip device operable to efvfect automatic operationoi' said breaker, said trip device' comprising an' energizing Wind1ng,an armature operable to effect tripping of said breaker, meanscomprising a sealed casing containing a body of, iluid, said casingbeing movable upon energization of seid winding to eiect operation ofsaid armature, time delay means for retardingmovement of said casingcomprising a magnetizable core within said casing disposed to berestrained against movement by energization Yo! said winding, said corehaving a passage therein .permitting fluid to flow from one end of saidcasing to the other, valve means for controlling ,the rate of flow ofsaid fluid to thereby control the rate'of movement of said casing, andmeans for adjusting said valve means to vary the rate of flow o! saidiluid to thereby vary the operating characteristic of said trip device.

'20. In a circuit breaker comprising relatively movable contacts andoperating means therefor, the combination of a trip device operable toeffect automatic operation of said breaker, said trip device comprisingan energizing winding, an armature operable to effect tripping of saidbreaker, means comprising a sealed casing containing a body of uid, saidcasing being movable upon energization of said winding to eiectoperation oi' said amature, time delay means for re trding movement ofsaid casing comprising a magnetizable core Within said casing disposedto be restrained against movement by energization of said winding, saidcore having a passage therein permitting iluid to flow from one end ofsaid casing to the other, valve means for controlling the rate of ilowof said fluid tothereby control the rate o1' movement of said casing,spring means biasing said valve means to oppose ow of uid through saidpassage, and means for adjusting said spring means to vary the rate oi'flow of said fluid to thereby vary the operating characteristic of saidtrip device,

21. In a circuit breaker comprising relatively movable contacts andoperating mechanism therefor, the combination of a trip device operablein response to overload currents' to effect automatic opening operationof said circuit breaker, said trip device comprising an energizingwinding, a

i5y movable core member operable upon energization of said winding, asealed casing containing a body of iiuid movable by said movable core'member to effect tripping of the breaker, time delay means f forretarding tripping movementof said casing comprising a secondary coremember\ disposed within said casing to be restrained against movement byenergization of said winding, said secondary core member having apassage therein permitting fluid to flow from one end of said casing tothe other end and adjustable means associated with said passage to varythe flow of uidto there,-

by vary the rate of tripping movement of said casing.

22. In a circuit breaker comprising relatively movable contacts andoperating mechanism therefor, the combination of a trip device operablein response to overloadcurrents inthe circuit controlled -by the breakerto effect automatic operation of said operating mechanism, said tripdevice comprising an energizing Winding, a irst armature operable toeffect tripping ofthe breaker, means comprising a sealed casing`movableto cause tripping operation of said first armature, a second armatureoperable -upon energiza'tion of said windingto move .said casing, timedelay means comprising a piston within said casing 4responsive toenergization` of said winding to retard tripping movement' of saidcasing, calibrating means comprising a spring'biasing said secondarmature against movement. and adjustable means for varying thetensionof said spring to thereby vary the minimum overload currentrequired to move said casing, said iirstv armature when operated movingfree of said calibrating spring to trip the'breaker.

23. In a circuitl breaker comprising relatively movable contacts, thecombination of an electromagnetic trip device operable to eect automaticopening of said contacts, said trip device comprising an energizingwinding, a sealed casing containing a body of 'uid and movable to causetripping of said breakenan armature operable upon energization ofsaidwlnding in response to overload currents to move said casingfasecond armature disposed in said casing to be held against movement byenergization of said winding to re; strict displacement of said uid tothereby retard tripping movement of said casing with a relatively longtime delay, land valve means operable to increase the rate ofdisplacement ofvuid to thereby retard tripping movement of said casingwith a relatively short'time delay.

24. In a circuit breaker comprising relatively movable contacts, thecombination oran electro-- magnetic trip device, operable to effectautomatic opening of said contacts, said trip device comprising anenergizing winding, a sealed casing containing a. body of uid andmovable to cause tripping of said breaker, an armatureoperable uponenergization of said winding in response to overload currents to movesaid casing, a second armature disposed in said basins to lbe heldagainst y movement by energiztion of said winding to restrictvdisplacement o! said iluid to thereby retard tripping movement o! saidcasing with a rela- 5 tively long time delay, valve means operable to-kincrease the rate of displacement of fluid to thereby retard trippingmovement of said casing with a'. relatively short time delay, andtripping means operable at times independently of said casing to linstantaneously trip said breaker. Y

25. In a circuit breaker comprising relatively movable contacts, thecombination of an eiectrcmagnetic trip device operable to eilectautomatic opening of said contacts. said trip device comprising anenergizing winding,'a sealed casing vcontaining a body-oi uid andmovable to trip` Y said breaker. a rst armature operable uponenergization of said winding in response to over "load currents to movesaid casing. a time delay 2'0 element having a fluid passagetherethrough dis posed in said casing and restrained against movement byenergization ot said winding to restrict y the ilow of iiuid t@ thereby.control the .rate oill tripping movement ofsaid casing. in response to'Yoverload currents below a predetermined value.

"s andla bypass valve in said passage for controlling the flow of uid totherebyl control therate o tripping movement of said casing in responseto overload currents above said predetermined value. 3Q 26. In a circuitbreaker comprising relatively movable contactshthe combination of anel'ectromagnetic trip-device operable to eect automatic trippingmovementof said casing in response to' overload currents below a predeterminedvalue,

a bypass valve in s'aid passage for controlling the ow of uid to therebycontrol the rate of tripping movement of said casing in response tooverload f currents above said predetermined value, and a. secondarmature operable at times independently breaker.

-f LINDSM.

mi* H. BAYLIS.

:mi wilt ENCES @Hm The following references are of record in the fileoi' this patent;

Number Name i A 2,072,932 Wilkens M5129, 1937 2,373,998 Elllwin '.a pl.17, 1945 of said ilrst armature to instantaneously trip said

